An Eagle Scout, Leebron was influenced by a steady stream of exchange students in his house—from Europe, Japan and Mexico—to develop an interest in international affairs.

[7] After graduating from Harvard Law, Leebron clerked for Judge Shirley Hufstedler in Los Angeles at the U.S. Ninth Circuit Court of Appeals.

He then re-entered academia as a law professor at New York University and the director of NYU's International Legal Studies Program from 1983 to 1989.

As a professor, he taught and published in areas of corporate finance, international economic law, human rights, privacy and torts.

Under Leebron’s leadership, the campus has added two new residential colleges; the 10-story[9] BioScience Research Collaborative, where scientists and educators from Rice and other Texas Medical Center institutions work together; a new recreation and wellness center; an additional food servery; a central campus pavilion that serves as a meeting and study place; an updated sports arena; a new physics building; and the Public Art Program, a presidential initiative that has added art across campus, although the University suffered a disappointing setback when merger talks between Baylor College of Medicine and Rice stalled.

In November 2008, Leebron traveled to Iran as part of an academic tour sponsored by the Association of American Universities.

On this four-day tour, he visited Sharif University, Iran's top engineering school, where he took part in an open question and answer session with Iranian students.